The site claims a fully operational Darth Vader chest piece and helmet have been created for Star Wars: Episode VIII, with it also said a LucasFilm team is going to train Hayden Christensen as Vader. It's also been suggested Vader may have some sort of role in the Star Wars anthology, Rogue One, which takes place between Episodes III and IV.
Hayden Christensen, of course, played Anakin Skywalker in the prequels.
Whether the rumor is true is anybody's guess, but as seen in Episode III, when Anakin became Darth Vader, the voice of James Earl Jones was used. By suggesting Hayden Christensen is going to be used implicates at the least his face will be seen on screen. Will Christensen's voice be used when the mask is off? It's also possible the scene could be short as, according to the rumor, only one Darth Vader suit was created, when in previous movies, numerous Darth Vader suits were used for filming.
Darth Vader is easily the most recognizable character in Star Wars, does the Disney merchandising machine want to capitalize on Darth Vader's brand recognition as much as possible?
"Star Wars: Episode VIII" has a May 26, 2017 release directed by Rian Johnson.